Typically, slip seat cushions in the furniture industry are made of a piece of foam secured on top of a wood board and polyester material on the foam all surrounded by a cover. Slip seat cushions are typically secured with screws to a furniture piece such as a chair for easy removal.
To obtain a desired crown or bowed portion in the cushion, additional foam has been added to the center of the cushion. One disadvantage of using such additional foam is that foam is relatively expensive; foam cost has been rising significantly faster in recent history than most other types of raw materials. The cost of foam is more volatile in general than other types of cushion components. Foam scrap from the fabricating process is not fully recyclable—it can only be shredded for use in low-value products or for making re-bonded foam. Foam loses a significant portion of its support very early in its life cycle, so a foam core cushion will lose support characteristics quickly during its life cycle, and will continue to lose support over the entire life cycle, leading to decreased consumer satisfaction and increased consumer returns. Foam has significantly less push back when a load is removed, compared to the resistance of the foam when the load is applied—this is felt by the occupant as less push from a cushion when getting up from the seated position. Foam is difficult to manufacture with consistency, and any given lot of foam will vary in its density and firmness. Foam is the most flammable of the cushion component choices. Smoldering foam creates toxic and explosive gases. Burning foam creates toxic gases. Foam cannot be manufactured with any post-consumer recycled content. Used foam is not practical to recycle.
A pocketed coil spring assembly such as used in a mattress retains most of its support characteristics throughout its life cycle, so a cushion made with pocketed coils will retain more of its original support throughout its useful life. A pocketed spring assembly is more resilient than foam, pushing back with essentially the same force when a load is removed, as it resists the load when it is applied. Pocketed coils are more consistent in firmness than foam, so any cushion made with pocketed coil springs will typically be more consistent than a foam cushion.
It is therefore an objective of this invention to reduce the amount of polyurethane foam incorporated into an upholstered furniture cushion.
Another objective of this invention is been to provide a furniture cushion that incorporates a pocketed spring assembly into a cavity of a slip seat board.
Another objective of this invention is been to provide a furniture cushion that has a crowned center portion created by a pocketed spring assembly.